1#!/bin/bash
  2
  3# objdiff - a small script for validating that a commit or series of commits
  4# didn't change object code.
  5#
  6# Copyright 2014, Jason Cooper <jason@lakedaemon.net>
  7#
  8# Licensed under the terms of the GNU GPL version 2
  9
 10# usage example:
 11#
 12# $ git checkout COMMIT_A
 13# $ <your fancy build command here>
 14# $ ./scripts/objdiff record path/to/*.o
 15#
 16# $ git checkout COMMIT_B
 17# $ <your fancy build command here>
 18# $ ./scripts/objdiff record path/to/*.o
 19#
 20# $ ./scripts/objdiff diff COMMIT_A COMMIT_B
 21# $
 22
 23# And to clean up (everything is in .tmp_objdiff/*)
 24# $ ./scripts/objdiff clean all
 25#
 26# Note: 'make mrproper' will also remove .tmp_objdiff
 27
 28GIT_DIR="`git rev-parse --git-dir`"
 29
 30if [ -d "$GIT_DIR" ]; then
 31	TMPD="${GIT_DIR%git}tmp_objdiff"
 32
 33	[ -d "$TMPD" ] || mkdir "$TMPD"
 34else
 35	echo "ERROR: git directory not found."
 36	exit 1
 37fi
 38
 39usage() {
 40	echo "Usage: $0 <command> <args>"
 41	echo "  record    <list of object files>"
 42	echo "  diff      <commitA> <commitB>"
 43	echo "  clean     all | <commit>"
 44	exit 1
 45}
 46
 47dorecord() {
 48	[ $# -eq 0 ] && usage
 49
 50	FILES="$*"
 51
 52	CMT="`git rev-parse --short HEAD`"
 53
 54	OBJDUMP="${CROSS_COMPILE}objdump"
 55	OBJDIFFD="$TMPD/$CMT"
 56
 57	[ ! -d "$OBJDIFFD" ] && mkdir -p "$OBJDIFFD"
 58
 59	for f in $FILES; do
 60		dn="${f%/*}"
 61		bn="${f##*/}"
 62
 63		[ ! -d "$OBJDIFFD/$dn" ] && mkdir -p "$OBJDIFFD/$dn"
 64
 65		# remove addresses for a more clear diff
 66		# http://dummdida.tumblr.com/post/60924060451/binary-diff-between-libc-from-scientificlinux-and
 67		$OBJDUMP -D "$f" | sed "s/^[[:space:]]\+[0-9a-f]\+//" \
 68			>"$OBJDIFFD/$dn/$bn"
 69	done
 70}
 71
 72dodiff() {
 73	[ $# -ne 2 ] && [ $# -ne 0 ] && usage
 74
 75	if [ $# -eq 0 ]; then
 76		SRC="`git rev-parse --short HEAD^`"
 77		DST="`git rev-parse --short HEAD`"
 78	else
 79		SRC="`git rev-parse --short $1`"
 80		DST="`git rev-parse --short $2`"
 81	fi
 82
 83	DIFF="`which colordiff`"
 84
 85	if [ ${#DIFF} -eq 0 ] || [ ! -x "$DIFF" ]; then
 86		DIFF="`which diff`"
 87	fi
 88
 89	SRCD="$TMPD/$SRC"
 90	DSTD="$TMPD/$DST"
 91
 92	if [ ! -d "$SRCD" ]; then
 93		echo "ERROR: $SRCD doesn't exist"
 94		exit 1
 95	fi
 96
 97	if [ ! -d "$DSTD" ]; then
 98		echo "ERROR: $DSTD doesn't exist"
 99		exit 1
100	fi
101
102	$DIFF -Nurd $SRCD $DSTD
103}
104
105doclean() {
106	[ $# -eq 0 ] && usage
107	[ $# -gt 1 ] && usage
108
109	if [ "x$1" = "xall" ]; then
110		rm -rf $TMPD/*
111	else
112		CMT="`git rev-parse --short $1`"
113
114		if [ -d "$TMPD/$CMT" ]; then
115			rm -rf $TMPD/$CMT
116		else
117			echo "$CMT not found"
118		fi
119	fi
120}
121
122[ $# -eq 0 ] &&	usage
123
124case "$1" in
125	record)
126		shift
127		dorecord $*
128		;;
129	diff)
130		shift
131		dodiff $*
132		;;
133	clean)
134		shift
135		doclean $*
136		;;
137	*)
138		echo "Unrecognized command '$1'"
139		exit 1
140		;;
141esac